Foam mixing head

ABSTRACT

A nozzle assembly for injecting plastic constituents which foam upon contact into objects which are to be filled therewith, and for cleaning the nozzle at the conclusion of foaming, contains a mixing chamber of circular cross section and a valve plate through which the plastic constituents and the solvent enter the mixing chamber. The valve plate has flap-type check valves adapted to discharge the materials tangentially into and whirl the same in the mixing chamber.

Unlted States Patent 1 1 1111 3,881,657

Heimann May 6, 1975 [541 FOAM MIXING HEAD 2,953,248 9/1960 Troland 239 112 Inventor: Fred G e a Mt. Clemens, 3,176,922 4/1965 Decker 239/414 Primary ExaminerRichard A. Schacher [73] Assignee: Fruehauf Corporation, Detroit, Assistant ExaminerRobert Saifer Mich. Attorney, Agent, or FirmHarness, Dickey & Pierce 22 F] d: 1e Feb 14, 1974 ABSTRACT [21] Appl' 44260l A nozzle assembly for injecting plastic constituents which foam upon contact into objects which are to be 52 US. Cl 239/413; 239/404 filled wi h, n f r cleaning the nozzle at the 51 Int. Cl B05b 7/10 conclusion of foaming, contains a mixing Chamber of [58] Fi ld f S h 239/10 112 400 404 circular cross section and a valve plate through which 239/413 414 417 5 the plastic constituents and the solvent enter the mixing chamber. The valve plate has flap-type check [56] References Cit d valves adapted to discharge the materials tangentially into and the same in the mixing chamber.

2,890,836 6/1959 Gusmer et a1. 239/404 7 Claims, 8 Drawing Figures PExTEi=iTEBMAY BiSYS 3,881,657

sum 2 BF 2 FOAM MIXING HEAD BACKGROUND OF THE INVENTION Nozzles for injecting foamable constituents for the formation of foamed plastic present certain problems in that where the material is of a type which foams upon contact, it is desirable to thoroughly mix the constituents in the nozzle, but upon the conclusion of foaming it is necessary to thoroughly remove and clean the nozzle to prevent clogging. It is also necessary to prevent any contact between the constituents after intentional foaming has ceased, in order to prevent unwanted foaming in the nozzle.

The present invention has as its object the provision of an improved nozzle of the indicated character wherein the constituents are automatically thoroughly mixed within the nozzle itself and discharged thereform as an homogeneously mixed and foaming material, but wherein all contact between the materials ceases when intentional foaming stops, and which incorporates improved means for thoroughly emptying and cleaning the nozzle at the conclusion of intentional foaming.

Other objects and advantages will be apparent upon consideration of the present disclosure in its entirety.

BRIEF DESCRIPTION OF THE FIGURES OF DRAWING FIG. 1 is a longitudinal diametric sectional view of a nozzle incorporating the principles of the present invention;

FIGS. 2, 3, and 4 are sectional views taken substantially as indicated by the line and arrows IIII, IIIIII, and IV- IV, respectively, of FIG. 1 and looking in the direction of the arrows;

FIG. 3A is a sectional view taken substantially on the line IIIAIIIA of FIG. 3 and looking in the direction of the arrows;

FIG. 5 is a longitudinal diametric sectional view of the nozzle body on a somewhat larger scale;

FIG. 6 is an elevational view of the rear end of the nozzle body; and

FIG. 7 is an elevational view of the front of the nozzle body.

DETAILED DESCRIPTION OF THE PREFERRED FORM OF THE INVENTION Reference character 10 designates generally a nozzle body of circular cross section having at its rear end threaded socket portions 11, 12, 13. The coupling portions 11 and 12 are adapted to receive fittings as 14 for connecting thereto supply tubes as 15, 16 through each of which one of the constituents of a plastic of the type which foams when the constituents are mixed is adapted to be conducted. The socket 13 is adapted to be connected to a conduit 18 for a solvent liquid.

A forward discharge portion or nose piece 20 of the nozzle assembly is removably threaded to the main body portion 10 as indicated at 22. Nose piece 20 contains an axial bore 24 through which the constituents are discharged, and a generally cylindrical mixing chamber 25 formed as a counterbore at its rear end.

A second larger counterbore 26 at the rear of the mixing chamber 25 defines a shoulder 28 which, when the parts are assembled, confines and positions a valve disc 30 and a ported spacer disc 32. The valve disc 30 is formed of a relatively resilient plastic material, such as an acetal resin of composition (OCH derived by polymerization of formaldehyde and which is sold under the trademark Delrin. Alternatively a polytetrafluoroethylene and fluorinated ethylene-propylene copolymer sold under the trademark Teflon may be used. The disc incorporates integral flap-type check valves which open forwardly when material is fed outwardly under pressure from the supply tubes through the nozzle, but close to prevent backflow at other times. The flat valve 34 is positioned over the discharge port 37 in the disc 32. Port 37 communicates through a passage 38 in the body 10 with the socket 12 and supply tube 16. Flap valve is positioned over the port in the plate 32, which port is defined by the end of a passage 44 communicating with the socket 11 and supply tube 15. The valve 36 is positioned over the port 45 in the plate 32 which communicates via a passage 46 in the body 10 with the socket l3 and supply tube 18.

The flap valves 34, 35, 36 are formed by integral tongue-like portions of the disc 30. As best shown in FIGS. 3A the tongue 35 is integral with the disc 30 at the upper end of the tongue. The tongue 35, and the other tongues, 34, 36, which are similarly formed, may be cut by means of a jewelers saw. The characteristics of the plastic, and its thickness and the valve tongue dimensions are so chosen with relation to the supply pressures that the tongues are urged outwardly to an acute angle, to permit discharge of the materials with a tangential component, causing them to whirl in the mixing chamber, when the materials. are fed thereto under pressure.

During normal foaming operations no solvent is supplied, and the two foaming constituents emerging from the valves 34, 35 are whirled in the chamber 25 and forced out through the bore 24. When foaming is stopped, the solvent liquid is discharged through the valve 36 and is thereby whirled in the chamber 25 before passing out through the bore 24, to clean these parts.

This Detailed Description of Preferred Form of the Invention, and the accompanying drawings, have been furnished in compliance with the statutory requirement to set forth the best mode contemplated by the inventor of carrying out the invention. The prior portions consisting of the Abstract of the Disclosure and the Background of the Invention are furnished without prejudice to comply with administrative requirements of the Patent Office.

What is claimed is:

1. In a nozzle structure for discharging at least one fluid whose viscosity increases upon discharge, said nozzle having separate inlet passages for at least two fluids, one of which is a solvent for the other, and having a single outlet, improved means for preventing clogging of the nozzle, comprising, in combination, a mixing chamber of circular cross section interposed in the flow path between said outlet and both of said inlets, check valves between each inlet and the mixing chamber, said valves being located on a wall of the mixing chamber to prevent backflow from the chamber toward the inlets, the valve for the solvent being located near the periphery of the chamber and discharging thereinto with a tangential component to cause the solvent to whirl in the mixing chamber.

2. A nozzle structure as defined in claim 1 wherein both of said valves are of the flap type and open into the mixing chamber tangentially, whereby the fluids are discharged directly from the valves into the mixing chamber with a tangential component,

3. A nozzle structure as defined in claim 1 having separate inlet passages for at least three fluids. two of which are to be combined in the mixing chamber, and both of the valves for said two last-mentioned fluids are of the flap type and open into the mixing chamber tangentially, whereby the fluids are discharged directly from the valves into the mixing chamber with a tangen tial component.

4. A nozzle structure as defined in claim 3 wherein the mixing chamber is substantially coaxial with the outlet, said valves comprising hinged flap valves mounted on a wall on the inlet side of the chamber and opening directly thereinto.

5. A nozzle structure as defined in claim 4 wherein said wall is formed of relatively thin flexible material and the flap valves are integral therewith.

6. In a nozzle structure for discharging at least one fluid whose viscosity increases upon discharge, said nozzle having separate inlet passages for at least two fluids, one of which is a solvent for the other, and having a single outlet, improved means for preventing clogging of the nozzle, comprising, in combination, a mixing chamber of circular cross section interposed in the flow path between said outlet and both of said inlets, check valves between each inlet and the mixing chamber, said valves being located close to the mixing chamber to prevent backflow from the chamber toward the inlets, the valve for the solvent being located near the periphery of the chamber and discharging thereinto with a tangential component to cause the solvent to whirl in the mixing chamber, the mixing chamber being substantially coaxial with the outlet, said valves comprising hinged flap valves mounted on a wall on the inlet side of the chamber and opening directly thereinto.

7. A nozzle structure as defined in claim 6 wherein said wall is formed of relatively thin flexible material and the flap valves are integral therewith. 

1. In a nozzle structure for discharging at least one fluid whose viscosity increases upon discharge, said nozzle having separate inlet passages for at least two fluids, one of which is a solvent for the other, and having a single outlet, improved means for preventing clogging of the nozzle, comprising, in combination, a mixing chamber of circular cross section interposed in the flow path between said outlet and both of said inlets, check valves between each inlet and the mixing chamber, said valves being located on a wall of the mixing chamber to prevent backflow from the chamber toward the inlets, the valve for the solvent being located near the periphery of the chamber and discharging thereinto with a tangential component to cause the solvent to whirl in the mixing chamber.
 2. A nozzle structure as defined in claim 1 wherein both of said valves are of the flap type and open into the mixing chamber tangentially, whereby the fluids are discharged directly from the valves into the mixing chamber with a tangential component.
 3. A nozzle structure as defined in claim 1 having separate inlet passages for at least three fluids, two of which are to be combined in the mixing chamber, and both of the valves for said two last-mentioned fluids are of the flap type and open into the mixing chamber tangentially, whereby the fluids are discharged directly from the valves into the mixing chamber with a tangential component.
 4. A nozzle structure as defined in claim 3 wherEin the mixing chamber is substantially coaxial with the outlet, said valves comprising hinged flap valves mounted on a wall on the inlet side of the chamber and opening directly thereinto.
 5. A nozzle structure as defined in claim 4 wherein said wall is formed of relatively thin flexible material and the flap valves are integral therewith.
 6. In a nozzle structure for discharging at least one fluid whose viscosity increases upon discharge, said nozzle having separate inlet passages for at least two fluids, one of which is a solvent for the other, and having a single outlet, improved means for preventing clogging of the nozzle, comprising, in combination, a mixing chamber of circular cross section interposed in the flow path between said outlet and both of said inlets, check valves between each inlet and the mixing chamber, said valves being located close to the mixing chamber to prevent backflow from the chamber toward the inlets, the valve for the solvent being located near the periphery of the chamber and discharging thereinto with a tangential component to cause the solvent to whirl in the mixing chamber, the mixing chamber being substantially coaxial with the outlet, said valves comprising hinged flap valves mounted on a wall on the inlet side of the chamber and opening directly thereinto.
 7. A nozzle structure as defined in claim 6 wherein said wall is formed of relatively thin flexible material and the flap valves are integral therewith. 